Redfish Catch Results from the Summer 2009, 2011 and 2014 Surveys in Unit 2

Transcription

1 Canadian Science Advisory Secretariat (CSAS) Research Document 2016/019 Newfoundland and Labrador Region Redfish Catch Results from the Summer 2009, 2011 and 2014 Surveys in Unit 2 D.W. Kulka and D.B. Atkinson Science Branch Fisheries and Oceans Canada PO Box 5667 St. John s, NL A1C 5X1 February 2016

2 Foreword This series documents the scientific basis for the evaluation of aquatic resources and ecosystems in Canada. As such, it addresses the issues of the day in the time frames required and the documents it contains are not intended as definitive statements on the subjects addressed but rather as progress reports on ongoing investigations. Research documents are produced in the official language in which they are provided to the Secretariat. Published by: Fisheries and Oceans Canada Canadian Science Advisory Secretariat 200 Kent Street Ottawa ON K1A 0E6 Correct citation for this publication: Her Majesty the Queen in Right of Canada, 2016 ISSN Kulka, D.W., Atkinson, D.B Redfish Catch Results from the Summer 2009, 2011 and 2014 Surveys in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/016. v + 32 p.

3 TABLE OF CONTENTS ABSTRACT... IV RÉSUMÉ... V INTRODUCTION... 1 METHODS... 2 SURVEY IN 2009 AND SURVEY IN SAMPLING... 3 CALCULATION OF BIOMASS AND ABUNDANCE... 3 RESULTS AND DISCUSSION SURVEY SURVEY SURVEY... 4 ALL YEARS... 5 MANAGEMENT AREAS... 7 SUMMARY... 7 ACKNOWLEDGMENTS... 8 REFERENCES... 9 APPENDIX I - TABLES APPENDIX II - FIGURES iii

4 ABSTRACT Within redfish management Unit 2 (portions of North Atlantic Fisheries Organization (NAFO) Subdiv. 3Pn, 3Ps, 4Vn, and 4Vs), the Groundfish Enterprise Allocation Council (GEAC) has funded redfish surveys since These surveys are the only available index of Unit 2 stock condition given the Department of Fisheries and Oceans (DFO) last surveyed Unit 2 redfish in GEAC funded and performed the surveys with scientific guidance from DFO in the design and execution of stratified random surveys and associated sampling. The data collected during these surveys have been subsequently analyzed on behalf of GEAC with the additional intent of providing this information to DFO, for their databases and future assessment work. The 9 th, 10 th and 11 th such GEAC redfish surveys in Unit 2 were completed in 2009, 2011 and Survey catch statistics, length distribution, and stratified analysis estimates of redfish abundance and biomass, and interpretation of results are presented for those years and compared to previous surveys. In most years, largest catches were observed south in the Laurentian Channel and along the shelf edge. Only in 1998 were large catches observed in the north adjacent to Unit 1. Normally, nearly all biomass was concentrated along the shelf edge. Interannual variations in distribution suggest that the fish move around within Unit 2 but are generally more concentrated in the south. Overall, in Unit 2, the total biomass index has fluctuated without trend since the early 2000s. For 2011, biomass was 119 kt up from 110 kt in 2009 but remains below the 2001 estimate of 141 kt. The abundance index also fluctuated without trend since the early 2000s. Total abundance of 372 M in 2011 is the highest since 2001 but remains well below values. In 2005, a nine cm peak of fish was observed indicating the presence of much younger fish than previously observed in significant numbers, likely fish that were two year olds. That peak persisted and increased in size through This suggested the presence of a significant 2002 year class. Change in survey gear and platform in 2014 makes the numbers noncomparable to previous years. The new Campelen gear likely has a substantially different q (catchability) compared to the particularly in terms of abundance at length. iv

5 Résultats des prises de sébaste tirés des relevés de l'été 2009, 2011 et 2014 dans l'unité 2 RÉSUMÉ Dans la zone de gestion 2 (parties des sous-divisions 3Pn, 3Ps, 4Vn et 4Vs de l'organisation des pêches de l'atlantique Nord-Ouest) du sébaste, le Conseil des allocations aux entreprises d'exploitation du poisson de fond (GEAC) finance des relevés sur le sébaste depuis Ces relevés constituent le seul indice disponible de l'état du stock de l'unité 2, étant donné que Pêches et Océans Canada a effectué le dernier relevé sur le sébaste de l'unité 2 en Le GEAC a financé et réalisé les relevés avec l'aide de Pêches et Océans Canada, qui a fourni des conseils scientifiques pour la conception et la réalisation des relevés aléatoires stratifiés et des échantillonnages connexes. Les données ainsi recueillies ont été analysées pour le compte du GEAC, et en vue de les transmettre à Pêches et Océans Canada pour les bases de données et les futurs travaux d'évaluation. Les 9e, 10e et 11e relevés du GEAC sur le sébaste dans l'unité 2 ont été achevés en 2009, 2011 et Le document présente des statistiques sur les captures, la répartition par longueur et des estimations par analyse stratifiée de l'abondance et de la biomasse du sébaste ainsi que l'interprétation des résultats pour ces années et par rapport aux relevés précédents. Pour la plupart des années, les prises les plus importantes ont été observées au sud du chenal Laurentien et le long du bord du plateau. Des prises importantes ont été observées dans la zone nordique située à côté de l'unité 1 en 1998 seulement. Normalement, presque toute la biomasse se trouve le long du bord du plateau. Les variations interannuelles en matière de répartition laissent supposer que les poissons se déplacent dans l'unité 2, mais ils se trouvent plus souvent au sud. Dans l'ensemble, l'indice de la biomasse totale pour l'unité 2 a fluctué sans présenter de tendance depuis le début des années En 2011, la biomasse était de 119 kt, supérieure à celle de 110 kt enregistrée en 2009, mais elle reste inférieure à l'estimation de 2001 de 141 kt. L'indice d'abondance a également fluctué sans présenter de tendance depuis le début des années L'abondance totale de 372 millions en 2011 est le niveau le plus élevé depuis 2001, mais il demeure bien en deçà des valeurs de En 2005, un poisson d'une longueur record de 9 cm a été relevé, indiquant la présence de poissons beaucoup plus jeunes que ceux observés auparavant en grand nombre, soit probablement des poissons âgés de deux ans. Ce record en matière de taille est devenu une tendance et la croissance de la taille a persisté jusqu'en Cette tendance suggère la présence d'une importante classe d'âge en En raison des modifications apportées à la plateforme et aux engins de relevé en 2014, les chiffres sont incomparables à ceux des années précédentes. Les nouveaux engins Campelen sont probablement considérablement différents en matière de capturabilité (q) par rapport aux engins, particulièrement sur le plan de l'abondance selon la longueur. v

6 INTRODUCTION Redfish comprise a complex of three species, Sebastes mentella, S. fasciatus (plus heterozygotes, a hybrid) and Sebastes marinus in Canadian Atlantic waters. All of those species/hybrids occur and intermix within redfish management Unit 2, (as well as Unit 1), a management area that encompasses NAFO Div. 3Ps, 3Pn, the Laurentian Channel portion of 4V and 4W fgj (Fig. 1a) (McAllister and Duplisea 2012). The majority of those fish occupy the deepest parts of the Unit 2 in and around the Laurentian Channel, just outside the Gulf of St. Lawrence (McClintock and Teasdale 2007). Redfish fishery management in the Laurentian Channel and surrounding areas has a complex history. Redfish was formerly managed as three units: Div. 4RST, Div. 3P, and Div. 4VWX (Atkinson and Power 1991). In 1993, based on observed fish movements, management units were redefined: Unit 1-4RST and 3Pn4Vn from Jan. to May; Unit 2-3Ps4VsWfgj, and 3Pn4Vn from June to Dec. Recent research however, has shown no genetic differences between Unit 1 and Unit 2 for each species. Two zonal reviews in 2010 concluded that Units 1 and 2 correspond to a single biological population of each species (DFO 2010, 2012). However, McAllister and Duplisea (2012) noted that Other work indicates that the Unit 1 and Unit 2 area may have important substock structure and some components of the stock (Unit 1) appear to be more depleted than others.fishing or allowable by-catch on this stock should account for its overall status as well as that of sub-components. Units 1&2 are currently assessed as a single stock but they remain managed" as separate stocks, i.e. separate TACs and separate quotas shares. Thus, even though Unit 1 and 2 are presently considered a single biological stock, it is deemed useful from a fishery management point of view to examine the Unit 2 portion on its own where fish appear less depleted than to the north. Following on the re-definition of stock structure for Redfish in the Laurentian Channel and surrounding areas, starting in 1997, Fisheries and Oceans (DFO), Newfoundland and Labrador (NL) Region implemented a Unit 2 redfish survey in Div. 3Pn and 4V, to cover most of the remaining Unit 2 stock area within the Laurentian Channel and surrounding locations, in addition to the annual standard spring survey that covers most of Subdiv. 3Ps (an area consistently surveyed by DFO since 1972) but not all parts of the Laurentian Channel. However, this DFO Unit 2 survey ended in The Groundfish Enterprise Allocation Council (GEAC) has operated industry redfish surveys in Unit 2 also since 1997, initially intended to be complementary to DFO Unit 2 redfish surveys. However, given that DFO has not conducted its Unit 2 (non-3ps) portion of the survey since 2002, the GEAC surveys taking place in NAFO Subdiv. 3Pn, 3Ps, 4Vn, and 4Vs, during winter 1997, and summer/fall 1998 to 2001, 2003, 2005, 2007, 2009, 2011 and 2014 now provide the only available up to date data that covers much of the key areas of Unit 2. The data collected during GEAC surveys have been analyzed and published providing survey results not only to industry but also to DFO, for their databases and assessment work. The information presented in this document follows on previous GEAC generated reports: for surveys (Power 1999), 2000 (McClintock 2000), 2001 (McClintock 2001), 2003 (McClintock 2003), 2005 (McClintock 2005) and 2007 (McClintock and Teasdale 2007). Based on data collected in 2009, 2011 and 2014 and consistent with surveys from previous years, this paper constitutes the ninth report describing results of the GEAC redfish survey series in Unit 2. 1

7 METHODS GEAC has performed a series of surveys in Unit 2 with scientific guidance from DFO both in the design and execution. The 170 survey gear was used for the GEAC Unit 2 survey (Table 1). However, DFO Unit 2 surveys done in used a different gear, the Campelen 1800 survey trawl with a 12.7 mm liner in the lower 7 m of the codend. A stratified random survey design similar to that used by DFO (Smith and Somerton 1981) was applied to the GEAC surveys: using a subset of survey strata illustrated in Fig. 1c and listed in Table 2 and 3. DFO preselected sampling locations within each designated stratum and the survey attempted to sample each of those sites. Fig. 1a shows the extent of Unit 2 and Fig. 1b shows depth contours and NAFO Divisions in relation to Unit 2. The GEAC surveys up to 2014 employed (45-50 m) large Cape class commercial trawlers (MV Cape Beaver or Cape Ballard) as the survey platforms: beginning in Dec 1997, switching to Aug and/or Sep annually from 1998 to 2001 (Table 1). SURVEY IN 2009 AND 2011 During September/October 2009 and September/October 2011, the Cape Ballard deployed an 170 trawl with a 30 mm liner in the lower 7 m of the codend and a 21 m (69 ft) wingspread, as was done on all previous Unit 2 GEAC surveys. Comparative fishing trials were conducted in August 2000 between the Cape Beaver and the CCGS Teleost and these results were modeled to provide a length-based conversion of the GEAC series from 2000 on into Teleost/Campelen equivalents (Cadigan and Power 2010). However, it is the (raw) data that are presented in this paper for all survey years as the data have yet to be converted for all years. SURVEY IN 2014 With all the Cape class vessels decommissioned, the 2014 survey was undertaken by the M/V Nautical Legend, a 19 m vessel during August/September, 2014, a change from larger survey vessels used between 1997 and This most recent GEAC survey changed not only the survey platform but also gear. The new trawl and foot gear used were based on the DFO Campelen trawl but updated with current trawl materials and modified to fit the smaller vessel. The vertical and horizontal openings are the same as the DFO Campelen trawl described above. Details of the gear configurations and materials are available from GEAC and DFO. Based on the comparative fishing work done in 2015, the wingspread of the GEAC Campelen was feet (15.2 m). That was the wingspread used for the 2014 survey analysis using the STRAP routines. The wing spread of the previously used survey trawl was 21 m. In view of the smaller size of vessel used in 2014, and to be consistent with DFO surveys, trawl durations were set to 15 minutes and tow speeds were kept between 2.8 and 3.2 knots for that year. Survey tows were monitored using Netmind and esonar net monitoring equipment. All equipment was calibrated and tested prior to the survey. This industry Campelen gear employed in 2014 is much closer in terms of its configuration to the DFO Campelen survey gear than the gear used in previous years. Comparative fishing trials with the DFO Campelen gear to calibrate catchability were completed in 2015 but analyses of these comparative data have yet to be undertaken undertaken. 2

8 SAMPLING Catch numbers and weight of redfish were recorded for each set. Redfish in each set were counted, weighed and sampled for length (by 1 cm) and for sex during the 2009, 2011 and 2014 trips, similar to previous surveys. Because S. mentella and S. fasciatus are very similar and difficult to distinguish at sea, they were coded as a single entity for the purpose of the analysis. S. marinus were rare and were not recorded. Not differentiating S. mentella and S. fasciatus is consistent with previous years analyses of GEAC survey data although DFO surveys in Unit 1 do differentiate between the two species by using fin ray count subsamples. McClintock and Teasdale (2009) did propose a method to apportion the GEAC 2007 abundance and biomass estimates into species components, for illustrative purposes but are not applied here. CALCULATION OF BIOMASS AND ABUNDANCE The set details and redfish length frequencies were exported from FFS (at sea data collection software, Fisheries Forms System) to create ASCII digital data files. Stratified random survey analysis was carried out using RStrap routine (STRAP programmed in R, R Core Team 2015) provided by DFO (based on Smith and Somerton 1981) and applying (subtracting) the French Exclusion Zone around St. Pierre et Miquelon for area calculations. All set catches using gear ( ) were standardized to a 30 minute tow and to a 15 minute tow for the 2014 Campelen survey. RStrap was used to calculate STRAP2 (non-length based biomass and abundance output), on a stratum by stratum basis and overall, namely, the relative abundance and biomass, mean numbers and weight per tow and confidence intervals (CI). For the 2009 and 2011 survey data, a wingspread of 69 ft (21 m) (3.5 knots during a 30 minute tow) was used, consistent with the analyses, same as past years. For the 2014 Campelen survey, a wingspread of ft (15.2 m) and tow length at 3 knots (a range of 2.8 and 3.2 knots) during a 15 minute tow) was used to calculate the swept area. Wingspread of m was used based on the net parameter information from comparative fishing done in May Length based output from STRAP includes stratum-by-stratum summaries of numbers at length separated by sex (male, female, unsexed) as well as overall sexes combined, including overall summaries of total numbers-at-length, mean numbers-at-length per tow and 95% CIs. Redfish were sampled in one cm length groupings and all ratio/percentages of catch measured were applied to provide a cm by cm estimate of catch. Output from STRAP that were not available for years prior to 2011 included mean number and weight/tow and associated CIs for Unit 2 area as a whole and thus are not presented. Distribution of the species was mapped using ACON for For 2011 and 2014, SPANS GIS (Anon 1997) was used to map the distribution. Scale was maintained between the two systems. Although the GEAC Unit 2 survey series now spans 17 years (11 sampled years), a number of inconsistences in the survey design have led to some limitations in interpreting the time series as a whole. a) No liner was used in 1997 to 1999 and thus primarily large fish would have been captured in those years; most fish smaller than about 19 cm escaped through the larger mesh (refer to Fig. 5 and 6). That would affect catch rate. b) Additional inshore strata SubDiv. 3Ps, strata, 295, 296, 298, 299 were sampled in 2007, 2009, 2011 and 2014 but not in previous years. The added strata were eliminated from RSTRAP analyses to ensure consistency among years. In 2014, stratum 309 was not 3

9 sampled and stratum 452 was sampled only in certain years. No adjustments were made when those strata were missed, consistently with previous analyses. c) Change in survey gear in 2014, from an 170 used in previous years to a Campelen trawl in 2014, makes the 2014 numbers non-comparable to previous years. A number of factors, particularly smaller mesh size used for Campelen, lead to size specific differences in catchability between gears. The new GEAC Campelen gear likely has a substantially different q (catchability) compared to the previously used gear, particularly in terms of abundance at length but it is similar to the DFO Campelen gear. d) The initial survey in 1997 was conducted at a different time of year. This should not affect overall survey abundance estimates unless fish are moving into or outside of the survey footprint. RESULTS AND DISCUSSION Table 2 provides an inventory of the Unit 2 survey set details for , including catch weight per set. See (Power 1999), 2000 (McClintock 2000), 2001 (McClintock 2001), 2003 (McClintock 2003), 2005 (McClintock 2005) and 2007 (McClintock and Teasdale 2007) for inventories from previous surveys SURVEY Of the 140 planned survey stations, a total of 126 sets were attempted. Redfish were caught in all sets. Of those, 126 were successfully completed and 117 sets were used for STRAP analyses (Table 2a). The 9 sets not used for STRAP occurred within nearshore strata that were first added in Since those strata were not sampled in previous years, to ensure a consistent survey footprint, they were excluded. Largest catches occurred in strata 707 and 708 in southern Subdiv. 3Ps (Table 2a, see Fig. 1b for location). The mean and median set catch numbers for the 2009 survey were 575 and 137 fish SURVEY A total of 138 of 140 planned sets were attempted. Of those, 136 were successfully completed and 127 sets were used for STRAP analyses (Table 2a). Redfish were caught in all sets. The nine sets that occurred within the nearshore strata that were first added in 2007 were excluded as was done for Largest catches occurred in strata 452 and 399 in Subdiv. 4Vs and 708 in Subdiv. 3Ps as for 2009 in the southern extent of the survey area (Table 2b, see Fig. 1b for location). The mean and median set catch numbers for the 2011 survey was were 802 and 135 fish (compared with 575 and 137 in 2009) SURVEY A total of 118 of 140 planned sets were attempted. Of those, 114 were successfully completed (Table 2c). Redfish were caught in all sets. Eight sets occurred within nearshore strata that were first added in As in previous years, they were excluded from the STRAP analysis. Largest catches occurred in stratum 303 in Subdiv. 3Pn and 451 Subdiv. 4Vs. The mean and median set catch numbers were 351 and 72 fish. Catch for this survey is not comparable to earlier years due to the change in vessel/gear. 4

10 ALL YEARS Table 3 shows mean catch per tow across all years of the GEAC survey by Subdiv. and by strata. In 2009, the largest mean catch/tow, reflecting high local density, occurred in Subdiv. 3Ps in stratum 708 (highlighted by grey shade) at the bottom of the Halibut Channel and was more than four times greater than in any other stratum (see Fig. 1c). As a result, the highest Subdiv. catch rate was observed in 3Ps in In 2011, local density was less concentrated and high catch rates were observed over a wider area. The largest catch rate again occurred in stratum 708 where catch rate was more than three times higher than any other stratum in 3Ps. However, relatively high rates were also observed in Subdiv. 4Vs primarily in strata 399, 452 and 468 (highlighted by grey shades). Those strata occur on the southern edge of the Scotian Shelf on the other side of the Laurentian Channel from St Pierre Bank and stratum 708 (see Fig. 1a). Between 1997 and 2005, stratum 452 was not sampled but in 2007 and 2009 when it was sampled, the values were only about 14% of the 2011 value. In strata 399, the 2011 value was five times higher than in There was only one set in 468 in 2009 and thus no value is available for that area to compare. Over all years, strata 399 and 468 usually dominated within 4Vs. On average, in 4Vs and 3Ps, particularly in strata near the mouth of the Laurentian Channel yield a greater portion of the biomass compared to the northern Subdivisions. Overall Unit 2 mean catch rate in 2009 was 172 kg/tow. The greatest consistent contribution of any stratum is from 708 by almost an order of magnitude more than any other stratum. The survey results for 2014 cannot be directly compared to previous years in terms of their magnitude but as in previous years, the largest catches were taken in Subdiv. 4Vs and 3Pn but the difference was not as dominant (Table 3). The strata with the largest catch/tow were 309 and 707 in 3Ps and 451 and 468 in 4Vs. Catches were more evenly spread among strata than in previous years. Unit 2 encompasses the outer reaches of the Laurentian Channel and surrounding shelf within Subdivisions 3Pn, 4Vn, 3Ps and 4Vs (Fig. 1). The Channel is a relatively flat deep trench with deepest locations of 450 m. Distribution of the catches is described by ACON plots (Fig. 1d) where catch for each survey location is depicted by expanding circles, larger circles, larger catches. In all years large catches are observed along the shelf edge leading east and west away from both sides of the Channel and also sometimes at the Channel mouth (Fig. 1d). In 1997, 2000, 2007 and 2009, large catches were observed mid to south in the Laurentian Channel. From Channel catches were generally small. Only in one year, 1998 were large catches observed in the north adjacent to Unit 1. In 2009, the redfish were highly concentrated at the eastern and western edge of the mouth of the Laurentian Channel. In 2011, the observed distribution was unusual in that no large catches were observed within the Channel: nearly all biomass was concentrated along the shelf edge in 3Ps and 4Vs. In 2014, the catches were spread throughout much of the Channel and shelf edge. These interannual variations in distribution indicate that the fish regularly move around within the Unit area. It should be noted that the surveys did occur at a different time of year in December in 1997, then in August or August/September or September/October in subsequent years. Figure 2 shows the mean weight per set together with 95% upper and lower confidence limits for the estimate. Mean values in 2009 range from 90 kg/tow in 4Vn to 146 and 149 kg in 4Vs 5

11 and 3Pn respectively, to 252 kg/tow in 3Ps. In 4Vs, the mean weight/tow was 91% of the 2007 survey value. Mean weights all increased in 2009 in the other three Subdivisions: the 3Ps value increased 20%, the 4Vn value 30%, and the 3Pn value over four times. In 2011, catch rate was lower in 2 (3Ps, 3Pn) of four Subdivisions. Wide confidence intervals mean limited information on trends in the population. Survey biomass and abundance are enumerated in Table 3 and illustrated in Fig. 3 by Subdiv. It is apparent that Subdiv. 3Pn, the smallest of the areas contains the least biomass and abundance: 4Vn and 4Vs, the southern extent of Unit 2 are about equally apportioned and on average contain about 76% of the abundance over the period of the surveys. With the highest values in 1997 and 1998, both biomass and abundance estimates have fluctuated without trend since about In Unit 2, the total biomass index appears to have fluctuated without trend since the early 2000s. For 2011 biomass was 119 kt up from 110 kt in 2009 but remains below the 2001 estimate of 141 kt. (Fig. 4). Because of the gear change in 2014, that year is not comparable to earlier years and thus the 2014 points are not joined to 2011 in Fig. 2 or Fig. 4. All of the spatial changes illustrated in Table 3, Fig. 1d, Fig. 2 and Fig. 3 indicate that although the majority of the biomass and abundance usually resides in southern Unit 2 and redfish tend to shift about among the four Subdivisions that make up the stock area. Figure 5 presents the redfish survey mean number at length by Subdiv. for each year of the Unit 2 surveys. Fish generally ranged between 15 and 45 cm with peaks in the upper range at about cm. Exceptions were in 2001 in 3Pn, 2005 in 3Pn and 4Vn, in 2007 in 3Ps and 3Pn 4Vn in 2014 when smaller fish were observed. These smaller peaks are evidence of the presence of younger year classes in substantial numbers in those years and this is discussed in more detail with respect to Fig. 6 below. Fig. 6 illustrates abundance at length by sex for each year of the survey. In most years, the length distribution generally peaked in the upper range of the length distribution, between 30 and 40 cm (fish mainly older than 15 years). A secondary smaller peak at about 25 cm was apparent in some years, evidence of the presence of younger fish (probably fish of about 8-13 years). In 2005, a peak ranging from 7 to 11 cm (9 cm max) indicated the presence of much younger fish than previously observed, likely fish that were two year olds. Escapement of fish in this size range from the gear is high given the larger mesh size and thus their presence in the net suggests very large numbers present in the water in that year. A large peak in the range of cm (15 cm max) in 2007 likely is the same year class that was first observed in 2005, now two years older. In 2009 there are three primary peaks evident. The largest is at 19 cm (for both male and females). A second peak is at 35 to 37 cm, and a lower, broader third peak is at 25 to 28 cm. A fourth very small peak is also evident at 15 cm. One can estimate, from average length at age based on research survey samples (data provided by Don Power) that these peaks might correspond to the , 1998 year classes and the 2003 year class noted above. In 2011, the largest peak at 22 cm (19-26 cm), likely comprising mainly nine year olds, corresponds again to that 2003 year class. Fish > 27 cm in 2011 were relatively at a much lower level of abundance indicating the importance of that 2002 year class in the population in that year. This suggests good recruitment occurred in 2002 and with that year class evident through to 2011, its persistence in the population. In 2014, fish abundance in the range of 9-17 cm in length amounted to 263 million fish but only four million in However, with the change in survey gear in 2014, the numbers are not directly comparable Campelen gear generally captures greater numbers of small fish. Fish in 6

12 that size range captured in the survey were also scarce in previous years (with the exception of 2005 when a small peak of fish in that range was observed) when gear was also used. This suggests the possibility of a large 2011 year class. Future surveys will determine if this is the case. MANAGEMENT AREAS Fishing effort in Unit 2 is managed spatially by the fishing industry to reduce the catch of S. mentella which is considered to be relatively less abundant than S. fasciatus. Current GEAC management measures allocate quota on the basis of statistical areas divided into two sectors, Northwest and Southeast areas (Table 4a). In 2011/2012, fishing effort by the >100 LOA fleet sector was allocated to Southeast area (3Psgh and 4Vsbc) where S. fasciatus is in greater proportion in the mix of the two species. The effect of concentrating effort in a particular area was examined by calculating biomass and abundance (species combined) for each of the Southeast and Northwest management areas. In order to partition the abundance and biomass estimates by those areas, individual strata estimates, the basic units for calculating biomass and abundance from the stratified random survey design, were allocated to each statistical area. In some cases, strata straddle the statistical area boundaries (see red numbers in Tables 4a). When this occurred, biomass and abundance estimates within those strata were allocated by half (by 1/3 rd in one case) to each statistical area that they overlapped. Given the gear change between 2011 and 2014, the results are not directly comparable. In 2011, biomass and abundance were roughly 50/50 between areas. In 2014, abundance was slightly higher in the SE while biomass was lower there (Table 4b, Fig. 7). In the Southeast sector, where fishing effort was purposely concentrated, the majority of biomass and abundance occurred in statistical area 4Vsc adjacent to the mouth of the Laurentian Channel. SUMMARY A full DFO assessment of Unit 2 redfish was last done in 2000 (Rice 2000), updates were last published in 2010 (DFO 2010) and 2012 (DFO 2012, Duplisea et al. 2012) and an RPA (Recovery Potential Assessment) was undertaken in 2012 (McAllister and Duplisea 2012). These most recent updates and the RPA incorporated data derived from the GEAC surveys up to This paper updates the raw GEAC survey and STRAP information on Unit 2 redfish to 2014 and provides a comparison to previous year s survey results. In most years, largest catches were observed south in the Laurentian Channel and along the shelf edge. Only in 1998 were large catches observed in the north adjacent to Unit 1. Normally, nearly all biomass was concentrated along the shelf edge. Interannual variations in distribution indicate that the fish move around within the stock area but are generally more concentrated in the south. Overall, in Unit 2, the total biomass index has fluctuated without trend since the early 2000s. For 2011 biomass was 119 kt up from 110 kt in 2009 but remains below the 2001 estimate of 141 kt. Overall, in Unit 2, the total abundance index has fluctuated without trend since the early 2000s.The total abundance estimate of 372 M in 2011 is the highest since 2001 but remains well below values. However, the 1997 survey did occur at a different time of year and a liner was not used in 1997 to 1999 which may in part account for the higher values observed. 7

13 In 2005, a peak at a length of nine cm was observed indicating the presence in large numbers of much younger fish than previously observed, likely fish that were two year olds. That peak persisted and increased in size through Fish > 27 cm in 2011 were relatively at a much lower level of abundance further indicating the importance of that 2003 year class in the population in that year. This suggested a significant 2003 year class. In 2014, a very large peak of fish at 9-17 cm possibly indicates a strong 2011 year class. On average in 2011 and 2014, both biomass and abundance were about equally distributed between the GEAC Southeast and Northwest management areas although it did vary between years. In the Southeast sector, the majority of biomass and abundance occurred in statistical area 4Vsc. A management implication is that the proportions may have changed over the last two surveys (three years) with a possible decrease in the proportion of the biomass and abundance in the southeast sector where the fishing effort has been concentrated since 2011/2012. ACKNOWLEDGMENTS The authors sincerely thank GEAC, Don Power, DFO and John McClintock for their assistance with provision of data. 8

14 REFERENCES Anon, SPANS. Vers. 7. Prospector Reference Manual. TYDAC Research Inc. Atkinson, D.B. and D. Power The redfish stock issue in 3P, 4RST and 4VWX. CAFSAC Res. Doc. 91/38. 47p Cadigan, N. G., and D. Power Vessel calibration results for redfish (Sebastes sp.) from comparative fishing between the Teleost research vessel and the Cape Beaver fishing vessel. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/062. DFO Assessment of redfish stocks (Sebastes fasciatus and S. mentella) in Units 1 and 2 in DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2010/037.. DFO Reference points for redfish (Sebastes mentella and Sebastes fasciatus) in the northwest Atlantic. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2012/004. Duplisea, D.E., Power, D. and Comeau P Reference points for eastern Canadian redfish (Sebastes) stocks. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/105 ii + 22 p. Groundfish Enterprise Allocation Council Unit 2 Perch Survey Draft Report. October 9, McAllister, M. and D.E. Duplisea Production model fitting and projection for Acadian redfish (Sebastes fasciatus) in Units 1 and 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2012/103 iii + 34 p. McClintock, J Redfish catch results from summer 2000 survey in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2000/133. McClintock, J Redfish catch results from summer 2001 survey in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2001/145. McClintock, J Redfish catch results from summer 2003 survey in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2005/061. McClintock, J Redfish catch results from summer 2005 survey in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2006/078. McClintock, J. and M. Teasdale Redfish catch results from the summer 2007 survey in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/094. Power, D The status of redfish in Unit 2. DFO Can. Sci. Advis. Sec. Res. Doc. 1999/155. R Core Team R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Rice, J Redfish Zonal Assessment Process. CSAS Proc. Series 2000/21. Smith, S.J. and G.D. Somerton STRAP: A User-Oriented Computer. Analysis System for Groundfish. Research Trawl Survey Data. Canadian Technical Report of Fisheries and Aquatic Sciences. No iv + 66p. 9

15 APPENDIX I - TABLES Table 1. GEAC Redfish Survey parameters, , - indicates a blank cell. Year Vessel Vessel length Period Gear Codend Liner Wingspread Tow Duration Tow Speed 1997 Cape Beaver m Dec 170 none 21 m 30 min 3.5 kts 1998 Cape Ballard m Aug/Sep 170 none 21 m 30 min 3.5 kts 1999 Cape Beaver m Aug/Sep 170 none 21 m 30 min 3.5 kts 2000 Cape Beaver m Aug/Sep mm 21 m 30 min 3.5 kts 2001 Cape Ballard m Aug/Sep mm 21 m 30 min 3.5 kts 2002 No survey Cape Beaver m Aug/Sep mm 21 m 30 min 3.5 kts 2004 No survey Cape Beaver m Aug/Sep mm 21 m 30 min 3.5 kts 2006 No survey Cape Ballard m Sep/Oct mm 21 m 30 min 3.5 kts 2008 No survey Cape Ballard m Sep/Oct mm 21 m 30 min 3.5 kts 2010 No survey Cape Ballard m Sep/Oct mm 21 m 30 min 3.5 kts 2012 No survey No survey Nautical legend 19 m Aug/Sep Campelen mm 15.2 m 15 min kts 10

16 Table 2a. Redfish catch details for GEAC stratified random survey sets, Unit 2, September Num is actual number caught in the set, Wt is actual weight caught (not adjusted to standard tow). Latitude and longitude are in decimal degrees, - indicates a blank cell. Latitude Longitude Stratum Div Num Wt (kg) Trip Set Depth (m) Bot Tem C Ps Ps 9,244 1, Ps 17,708 4, Ps 1, Ps 2, Ps Ps Ps Ps 2,440 1, Vs Vs Vs Vs Vs Vs Vs 2, Vs Vs Vs Vs Vs Vs Vs Ps Ps Ps Vs Vs Vs Vs Ps Ps 1, Ps Vs Vs Vs Vs Ps Ps 1,810 1, Vs Ps 1, Ps Ps Ps Vs Vs Vs Vn Ps Ps Ps Ps Ps Ps Vn 3, Vn Vn

17 Table 2a. Continued. Latitude Longitude Stratum Div Num Wt (kg) Trip Set Depth (m) Bot Tem C Ps Ps Ps Ps Ps Ps Ps Vn Vn Vn Vn Ps Ps Ps Ps Ps Ps Vn Vn Vn Vn Vn Vn Vn Vn Vn Ps Ps Ps Ps Ps Pn Vn Vn Vn Vn Pn Vn Vn Vn Vn Vn Vn Vn Vn Vn Vn Vn Pn Pn Pn Pn Pn Pn Pn Pn 1, Ps Ps Pn 1, Ps

18 Table 2b. Set by set redfish catches for GEAC stratified random survey sets, Unit 2, September Num is actual number caught in the set, Wt is actual weight caught. Latitude and longitude are in decimal degrees, - indicates a blank cell. Latitude Longitude Stratum Div Num Wt (kg) Trip Set # Depth (m) Bot Tem C V V 7, V 2, V V V V 4,567 1, V 8,406 2, V 1, V 4,453 1, V 1, V 2, V V V V V V U U U U U U U U U U U U U U U U U U U U U U U U U U U U U Q Q Q Q Q Q Q Q Q P P Q Q Q Q

19 Table 2b. Continued. Latitude Longitude Stratum Div Num Wt (kg) Trip Set # Depth (m) Bot Tem C P P P P P P P P P P U P U 1, P P P P P P P P P P P P P P P P P P U P P P P P P P V V V P P P P P P V V V P P V V V P P P P P 6,927 2, P P 1,

20 Table 2b. Continued. Latitude Longitude Stratum Div Num Wt (kg) Trip Set # Depth (m) Bot Tem C P P P 3, P Table 2c. Set by set redfish catches for GEAC stratified random survey sets, Unit 2, September Num is actual number caught in the set, Wt is actual weight caught. Latitude and longitude are in decimal degrees, - indicates a blank cell. Latitude Longitude Stratum Div Num Wt (kg) Trip Set # Depth (m) Bot Tem C Ps Ps Ps Ps Ps Ps Ps 1, Ps 1, Ps Ps Ps Ps Ps Ps Ps Ps 1, Ps 1, Ps Ps Ps Ps Ps Vn Ps Ps Ps Ps Ps Ps Ps Ps Ps Vs Vs Vs Vs Vs Vn 1, Vn Vn Vn Vn Vn Vn Vn Vn

21 Table 2c. Continued. Latitude Longitude Stratum Div Num Wt (kg) Trip Set # Depth (m) Bot Tem C Vn Vn Vn Vn Vn Pn Vn Vn Vn Vn Vn Vn Vn Vn Vn Pn 5, Vn Pn Pn Pn Pn Pn Pn Ps Ps Ps Ps Vn Ps Ps Ps Ps Vs Ps Ps Vs Vs Vs Vs Vs Vs Vs 1, Vs Vs Vs 1, Vs 2, Vs 1, Vs Vs Vs Vs Vs Ps 1, Ps Ps Ps 1, Ps Ps Ps Ps

22 Table 3. Mean weight (kg) of redfish caught per standard 30 minute tow in 1997 to 2011, 15 minute tow in 2014 and survey biomass in Unit 2 during GEAC surveys. "*" indicates strata not sampled, "x" indicates strata with less than 2 sets, indicates high catch rates, and - indicates a blank cell. Total abundance estimates are noted at the bottom of the table. Div. Depth Range Area Campelen 2014 STRAT. (m) sq. nmi. Dec Aug Aug 31- Sep 9 - Aug Sep Aug 26-Sep 5 - Aug Sep 20- Oct 7 - Sep Aug - Aug - 3Pn kg/tow Upper Mean Lower Biomass (t) - - 7,630-8,918-9,981-6,362-4,858-7,646-14,092-2,464-10,469-5,202-11,996-3Ps x * * x x x * * - x * * * * * ,

23 Table 3. Continued. Div. Depth Range Area Campelen * - * - * - * - * - * - * x kg/tow Upper Mean Lower Biomass (t) ,329-50,412-38,828-37,916-34,919-23,853-30,161-59,463-60,914-38,442-54,717-4Vn x kg/tow Upper Mean Lower Biomass (t) ,219-74,474-23,034-32,714-15,881-15,841-18,358-13,412-17,548-23,768-20,758-4Vs * - * * - * - * - * * - * - *

24 Table 3. Continued. Div. Depth Range Area Campelen * - * x 1 * - x kg/tow Upper Mean Lower Biomass (t) ,619-88,601-15,684-92,020-85,593-34,782-29,315-23,027-20,856-52,547-31,535 - Total # Sets Mean wt/tow (kg) Tot Surv Biomass (t) , ,405-87, , ,251-82,122-91,926-98, , , ,006 - Mean number/tow Tot Abundance (millions) % difference compared to the previous year - Biomass % difference compared to the previous year - Abundance % % - 48% - -20% - -72% - 11% - 7% - 10% - 8% % % - 43% - 21% % - 41% - 11% - -12% - 19% estimates from original CSAS Res Doc 2006/078 were updated in 2007 (see text in 2009/094) 19

25 Table 4a. Redfish abundance and biomass delineated by Strata within Northwest (NW) and Southeast (SE) Industry Management areas. Biomass is expressed in metric tonnes, abundance in numbers/1000. In some cases, strata straddle the statistical area boundaries, illustrated in red and *. - indicates a blank cell (NW) Div./SA Stratum 2011 (NW) Biomass 2011 (NW) Abundance 2011 (NW) # sets 2011 (SE) Div./SA Stratum 2011 (SE) Biomass 2011 (SE) Abundance 2011 (SE) # sets 2014 (NW) Div./SA Stratum 2014 (NW) - Biomass 2014 (NW) Abundance 2014 (NW) # set s 2014 (SE) Div./SA Stratum 2014 (SE) Biomass 2014 (SE) Abundance 2014 (SE) # sets 3Pn 5,202 9, Psg 6,520 20, Pn 11, , Psg 11,904 49, ,049 4, , , , ,362 8, , ,808 8, ,274 9, ,584 6, ,674 3, * 156* 436* 2* , not surveyed not surveyed 3Psa 9,354 21, * 1,054* 4,000* 3* 3Psa 16,931 67, * 2,922* 13,451* 2* 298* 1,539* 5,428* 1* 712 2,533 4, * 326* 2,072* 1* 712 2,510 6, * 1,631* 5,111* 1* 716* 624* 1,618* 1* 299* 267* 582* 1* 716* 3,525* 14,930* 1* 300 not surveyed not surveyed - 3Psh 14,776 44, ,405 3, ,425 5, not surveyed not surveyed not surveyed not surveyed not surveyed not surveyed - 3Psh 7,165 33, ,484 8, ,032 7, ,917 45, ,063 13, * 2,969* 4,118* 5* ,163 32, * 1,146* 2,001* 3* 708 2,618 12, * 1,186* 2,120* 1* 709* 156* 436* 2* 715* 751* 1,839* 2* 709 not surveyed not surveyed 716* 624* 1,618* 1* 4Vsb 8,255 16, * 3,525* 14,930* 1* 4Vsb 8,990 34, Psb 3,485 11, ,939 5, Psb 1,254 4, ,172 14, ,021 1, , ,049 1, * 3,295* 9,285* 1* * 1,768* 18,402* 1 298* 1,539* 5,428* 2* 4Vsc 42, , * 326* 2,072* 1* 4Vsc 23, , * 1,631* 5,111* 2* 398 4,594 17, * 267* 582* 1* 398 5,741 18, Psd 9,908 16, ,775 88, Psd 14,191 63, ,348 18, * 3,295* 9,285* 1* 313 1,685 17, * 1,768* 18,402* 1* , ,267 2, ,116 22, ,969 40,

26 Table 4a. Continued (NW) Div./SA Stratum 2011 (NW) Biomass 2011 (NW) Abundance 2011 (NW) # sets 2011 (SE) Div./SA Stratum 2011 (SE) Biomass 2011 (SE) Abundance 2011 (SE) # sets 2014 (NW) Div./SA Stratum 2014 (NW) - Biomass 2014 (NW) Abundance 2014 (NW) # set s 2014 (SE) Div./SA Stratum 713 4,017 5, ,171 65, ,968 4, (SE) Biomass not surveyed 2014 (SE) Abundance not surveyed 714* 2,969* 4,118* 9* 468 5,895 19, * 1,146* 2,001* 3* 468 4,951 18, * 1,186* 2,120* 1* 711* 1,054* 4,000* 3* 715* 751* 1,839* 2* 711* 2,922* 13,451* 2* 716* 624* 1,618* 1* * 3,525* 14,930* 1* Vn 27,063 46, Vn 22,526 84, ,341 25, ,099 16, ,186 5, ,711 19, ,241 5, ,948 29, * 3,295* 9,285* 1* * 1,768* 18,402* 1* Sum 55, , Sum 71, , Sum 66, , Sum 51, , (SE) # sets - % in area 43.4% 26.7% - % in area 56.6% 73.3% - % in area 56.4% 62.0% - % in area 43.6% 38.0% - Both areas 126, , Both areas 126, , Both areas 118, , Both areas 118, ,

27 Table 4b-1. Summary of redfish abundance and biomass delineated by Southeast Management areas. Biomass is expressed in metric tonnes, abundance in number/ Biomass Abundance Biomass Abundance 3Psg 6,520 20,400 11,904 49,930 3Psh 14,776 44,653 7,165 33,655 4Vsb 8,255 16,520 8,990 34,457 4Vsc 42, ,403 23, ,624 All 71, ,976 51, ,666 3Psg 9% 7% 23% 20% 3Psh 21% 15% 14% 14% 4Vsb 12% 6% 17% 14% 4Vsc 59% 72% 46% 52% % SE 57% 73% 44% 38% Table 4b-2. Summary of redfish abundance and biomass delineated by Northwest Management areas. Biomass is expressed in metric tonnes, abundance in number/ Biomass Abundance Biomass Abundance 3Pn 5,202 9,422 11, ,760 3Psa 9,354 21,504 16,931 67,232 3Psb 3,485 11,762 1,254 4,413 3Psd 9,908 16,693 14,191 63,842 4Vn 27,063 46,001 22,526 84,732 All 55, ,383 66, ,979 3Pn 9% 9% 18% 45% 3Psa 17% 20% 25% 17% 3Psb 6% 11% 2% 1% 3Psd 18% 16% 21% 16% 4Vn 49% 44% 34% 21% % NW 43% 27% 56% 62% Both areas 126, , , ,645 22

28 APPENDIX II - FIGURES Figure 1a. Extent of Unit 1&2 Redfish stock areas. Unit 2 constitutes the areas outside of the Gulf of St. Lawrence, the lower portion of the area, below the red line. Figure 1b. NAFO Divisions and depth contours in the vicinity of Unit 1 and 2 stock areas. Unit 2 occurs in 3Pn, 3Ps, 4Vn, 4Vs and a small portion of southeastern 4W mainly in and around the Laurentian Channel (red arrow). 23

29 Figure 1c. Stratum boundaries within the Unit 2 stock area. 24

30 Figure 1d. Redfish catch weight distribution from GEAC stratified random surveys, Unit 2, (200, 400, and 800 m depth contours are shown). A + indicates a tow with no redfish caught. 25

31 Figure 2. Mean weight (kg) of redfish caught per standard 30 minute tow for , 15 minute tow for 2014 from GEAC Unit 2 surveys. Ninety-five percent upper and lower confidence limits are also shown as vertical lines. The 2014 points are joined to the earlier years since survey gear changed in that year. Note the different (wider) scale for 4Vs. Unit 2 stock area data not available prior to

32 Figure 3. GEAC Unit 2 redfish survey catch estimates: 3a - relative biomass by year and Subdivision, 3b. - relative abundance by year and NAFO Subdivision. 27

33 Figure 4. Biomass and abundance indices for the GEAC survey series. No line joins 2011 and 2014 data points because of the change in survey gear and thus, estimates in 2014 are not comparable to earlier years. 28

34 Figure 5. Redfish numbers at length by Subdiv. from GEAC Unit 2 surveys for 1997 to X-axis is from 1-45 cm and y-axis is mean numbers of fish/tow at length, scaled 0 to 150 up to 2011 and 0-50 for Below the red line, a different survey gear was used. In , a liner was not placed in the trawl. 29

35 Abundance (millions) GEAC SURVEY DECEMBER 1-10 Male Female Unsexed Abundance (millions) GEAC SURVEY AUGUST Male Female Unsexed Abundance (millions) GEAC SURVEY AUGUST 31-SEPTEMBER 9 Male Female Unsexed Length (cm) Length (cm) Length (cm) Abundance (millions) GEAC SURVEY AUGUST Male Female Unsexed Abundance (millions) GEAC SURVEY SEPTEMBER Male Female Unsexed Abundance (millions) GEAC SURVEY AUGUST 26 - SEPTEMBER 5 Male Female Unsexed Length (cm) Length (cm) Length (cm) GEAC SURVEY AUGUST Male Female Unsexed GEAC SURVEY SEPTEMBER 20- AUGUST 7 Male Female Unsexed GEAC SURVEY SEPTEMBER Male Female Unsexed Abundance (millions) Combined Abundance (millions) Combined Unsexed (and combined) peaks at 53.4 M at 15 cm Abundance (millions) Combined Length (cm) Length (cm) Length (cm). Figure 6a. Redfish survey abundance index at length from GEAC Unit 2 surveys from 1997 to

36 Figure 6b. Redfish survey abundance (numbers) index at length from GEAC Unit 2 surveys for 2011 and 2014.Note that 2011 and 2014 were sampled by different gears, in 2011, Campelen in

37 Figure 7. Proportion of abundance and biomass by management area (refer to Table 3). 32